BROOKLINE - New England Treatment Access Inc. opened the doors of its medical marijuana dispensary here in February, after years of fighting with some residents and haggling with local government officials.

Around the same time that the NETA dispensary started admitting patients inside the former Brookline Bank building, a doctor specializing in medical marijuana quietly opened an office a five-minute drive away, on Brookline's Beacon Street.

So far, Dr. Jordan Tishler's practice has been largely unnoticed. Tishler, who also has an office in Cambridge on Massachusetts Avenue, is one of 136 doctors in Massachusetts registered with the state's medical marijuana program.

Voters approved marijuana for medical use in 2012, and state officials took their time with the licensing process.

There are six dispensaries now open in Massachusetts. Aside from the one in Brookline, there's one in Northampton (also owned by NETA) and the others are in Brockton, Salem, Ayer, and Lowell. Another 12 are in the inspection phase required by state regulators, all while at the federal level, marijuana remains a banned "Schedule I" drug.

"The state has been probably overly cautious but it's a new field and politically charged," Tishler said while sitting in his Cambridge office on a recent Wednesday.

His practice, "Inhale MD Health and Wellness," has 400 patients. "I'm stunned by how far patients will come to see me," traveling from New Bedford to Haverhill and Northampton, he said, adding that he had to send some to Maine before the dispensaries in Massachusetts opened.

The latest data available from the state Department of Public Health shows there are 26,137 certified medical marijuana patients in Massachusetts. Dispensaries have so far sold 23,766 ounces of medical marijuana, but patients have complained the state's ramp-up hasn't been fast enough.

Like state officials, doctors have also been leery of getting involved in medical marijuana.

Dr. Kevin Hill, an addiction psychiatrist, has staked out a middle ground within the medical community on the topic. "I don't think it should be a Schedule I drug, but there could be better evidence," he told MassLive.com. "If there were more studies done, I think more physicians would be willing to do it."

"Most physicians say this is a federally illegal narcotic and although no one has lost a court case yet or lost their license for certifying someone for a medical cannabis, why take the chance?" he added.

Tishler, 49, was an emergency room doctor at a local veterans' hospital when he heard the news of Massachusetts voters endorsing medical marijuana.

He said he started doing some "homework," and discovered "an astounding amount of scientific research" on cannabis. "We could always use more research. That's inarguable," he added.

Tishler said he doesn't have a typical patient - they range in age from a 20-year-old with Crohn's disease to an 80-year-old with rheumatoid arthritis.

Forty percent of his patients came through referrals, the rest arrive through word of mouth and advertising in local magazines.

His colleagues in the medical community have offered him "enthusiastic curiosity," since most don't know much about cannabis, according to Tishler. "Cannabis medicine is becoming a specialty unto itself," he said.

He recently toured the NETA shop in Brookline, which he referred to as pleasant and secure. "We're moving in the right direction for the care of patients," he said.

"I don't want to suggest cannabis is without risk," he added, stating that there is a risk of withdrawal symptoms, such as three to seven days of mood swings, irritability and trouble with sleep.

"You can't kill yourself with cannabis," he said. "But it can make you sick. That's the reality of any substance."

According to Dr. Hill, the addiction psychiatrist, people can become addicted to marijuana, and 9 percent of adult users do, losing spouses, multi-million dollar careers and educational opportunities.

Marijuana use can also lead to worsening anxiety, Hill added. "I'm not saying marijuana is as dangerous as opioids, but there needs to be more guidance and directions how to use it," he said.

By Hill's account, if medical marijuana was the state's mid-term, then Massachusetts has failed, which doesn't bode well for full-on legalization of recreational marijuana.

"We're eight months away and we've got a pretty lousy bill," he said, referring to the ballot initiative on track for statewide November ballot.

The initiative's tax rate is a problem for Hill, who says it's too low and the state could draw more money for education, prevention and treatment if it's higher. A panel of state senators last week recommended heavy taxation if the substance is legalized.

Backers of the initiative say a lower tax rate on legal marijuana is necessary to undercut the black market.

"To me, that's a red herring," since the black market will never be completely eliminated, said Hill, who added that he conceptually supports legalization.

Tishler said he backs legalization - Massachusetts voters could vote in November on whether recreational marijuana should be allowed - and added that adults should have the right to choose.

"Legalization is going to be a boon to patients," he said, since it will raise awareness of marijuana as a medicine.

He doesn't expect patients to stop taking medical marijuana and switch to using the recreational kind.

"Nobody needs permission to buy Tylenol, but people still go to the doctor," Tishler said.